This invention relates to an electrical connector, and in particular to an electrical connector suitable for use with live electrical conductors.
It is often necessary to connect one electrical conductor to an existing conductor, eg where a service cable is connected to an existing mains cable. To save time and avoid disruption of supply it is often desirable that this be done without removing the electrical supply to the mains cable, ie to make the connection while the mains cable is live. However, this obviously presents a safety hazard and special designs of connector are often employed to minimise or eliminate the risk to an operative engaged in making the connection. Various designs of such connectors have been proposed but none has been found to be completely satisfactory. For instance, such connectors either fail to provide satisfactory insulation (during or after installation) or have bulky insulated mechanisms leading to increased encapsulation costs.
There has now been devised an electrical connector which is suitable for use with live conductors and which overcomes or substantially mitigates disadvantages associated with the prior art.
According to the invention, there is provided an electrical connector comprising a connector body including a socket for an electrical conductor, the connector body having an electrically insulating shroud and having a threaded bore in which a connecting bolt is threadedly engaged, the connecting bolt being capable of actuation into engagement with a conductor inserted into the socket by means of a drive member engaged with the connecting bolt and extending through an opening in the insulating shroud to a rotatable, electrically insulating cap, wherein the connecting bolt is slidably mounted on the drive member, the drive member being adapted to shear at a position between the opening in the insulating shroud and the point of engagement of the drive member with the connecting bolt when a predetermined torque is applied to the drive member, such that the cap and a residual portion of the drive member attached thereto can be withdrawn from the opening in the insulating shroud, and the opening in the insulating shroud being adapted substantially to close after the drive member has so sheared and been withdrawn.
The connector according to the invention is advantageous primarily in that it reduces or eliminates the risk of exposure of an operative to electrically live surfaces during the fitting of the connector, even to an electrically live conductor. After installation the bulk of the insulated mechanism can be removed without exposing live metalwork, thus reducing the volume of encapsulant required without compromising the safety of the installer. The connector is nonetheless simple to use, and of compact design.
The connector body is of electrically conducting material, most commonly a metal such as aluminium or brass. The socket may be a bore formed in a unitary connector body. Alternatively, the socket may be defined by a channel between two components held in fixed relationship.
The connector body may include one or more sockets for receiving a corresponding number of conductors. Each such socket may be provided with one or more connecting bolts.
The insulating shroud applied to the connector body is most preferably a plastics coating. The shroud may be applied to the connector body, or to the components which make up the connector body, by any of a number of techniques. For example, the shroud may be formed as an injection-moulded component which snaps into place, or the body or component may be dipped in molten plastics material.
The connecting bolt is preferably formed on the end which engages the conductor with insulation piercing formations. This eliminates the need to strip insulation from the conductor before installing the connector and further reduces the risk of exposing the installer to live metalwork.
The drive member preferably comprises a pin or rod with a cross-section which is of non-circular, eg hexagonal, form, at least in its part which engages the connecting bolt. The drive member preferably engages in an axial bore of corresponding shape in the connecting bolt.
The drive member may be formed integrally with the cap, eg by being moulded with the cap in plastics material. Alternatively, the drive member may be formed in metal, eg brass or steel, and the cap may be moulded in plastics material about one end of the drive member.
The drive member is preferably provided with a local weakening, eg a waist or the like, which shears at a predetermined torque.
The electrically insulating shroud preferably covers the opening of the threaded bore, extending up to the portion of the drive member which extends through the shroud. In the region of the opening, the shroud preferably takes the form of a petal washer or the like, ie it is formed with a number of leaves which are resiliently deformed by the drive member but which relax to cover the opening of the threaded bore when the drive member shears and is removed with the cap. Such leaves may be formed as part of a separate bushing which is fitted into the opening in the insulating shroud.